1. Field of the Invention
Embodiments of the present invention generally relate to methods of manufacturing a write head for use in a magnetic disk drive and for a write head thereby produced.
2. Description of the Related Art
A perpendicular recording system records data as magnetizations oriented perpendicular to the plane of the magnetic disk. The magnetic disk has a magnetically soft underlayer covered by a thin magnetically hard top layer. The perpendicular write head has a main pole, sometimes referred to as a write pole, with a very small cross section and a return pole having a much larger cross section.
FIGS. 1A and 1B are schematic illustrations of a prior art write head 100. FIG. 1A is a schematic illustration of the prior art write head 100 as viewed from the air bearing surface (ABS) 118 (shown in FIG. 1B). FIG. 1B is a schematic cross sectional view of the write head 100 of FIG. 1A as taken along line A-A. The write head 100 includes a leading edge shield 102, side shield 104 and trailing shield 106 which collectively surround the main pole 108. The main pole 108 is also surrounded by a write gap layer 110, a high Bs seed layer 112 and a side gap layer 114. As can be seen from FIG. 1B, the main pole 108 is tapered towards the ABS 118. A non-magnetic reactive ion etching (RIE) stop layer 116 is also present. The RIE stop layer 116 typically comprises a non-magnetic material such as chromium or nickel-chromium. The RIE stop layer 116 is utilized in the damascene process that is used to fabricate the main pole 108.
FIGS. 2A-2D are schematic views of a prior art write head 100 as viewed from the ABS 118 at various stages of manufacture. In order to fabricate the write head 100, an insulating layer 202 is formed over the leading edge shield 102. The insulating layer 202 is patterned by performing an RIE process to etch a trench 204 into the insulating layer 202 using a mask 206. The RIE stop layer 116 prevents etching into the leading edge shield 102. The mask 206 is removed and then the side gap layer 114 and main pole 108 are formed as shown in FIG. 2B. The insulating layer 202 is then removed as is as much of the RIE stop layer 116 as possible as shown in FIG. 2C. The side shield 104 is then deposited as shown in FIG. 2D.
Damascene write head main pole fabrication for ultra density beyond 700 gigabytes per square inch need the leading edge shield 102 and the side shield 104 to improve adjacent track interference (ATI) and far track interference (FTI) as well as the performance of the write head. The non-magnetic RIE stop layer 116 controls the trench 204 depth and the main pole 108 thickness. Because all of the RIE stop layer 116 cannot be removed, the non-magnetic RIE stop layer 116 causes a magnetic separation between the leading edge shield 102 and the side shield 104. The more RIE stop layer 116 that is removed, the more processing steps that are required. Additionally, removing additional RIE stop layer 116 material can ruin the shape of the main pole 108 and oftentimes causes redeposition of the nonmagnetic material on the sidewall of the main pole 108.